Generally, the doors are connected to the structure of the aircraft by an articulatedly jointed arm and/or hinges. In order for a door to retain its function as sealing lid for the pressurisation of the cabin, it is necessary for it to not be subject to the torsion and flexion constraints that are applied on to the framework of the aircraft. This requires a decoupling of the door from the arm once the door is closed.
Moreover, the connection between the door and the arm must be robust in order to make possible the precise installing in position of the door at the level of the opening, in the door frame located around the opening. The connecting mechanism must therefore present a sufficient degree of stiffness, particularly at the level of the connection between the arm and the door in order to ensure the proper installing in position thereof.
In the aforementioned type of mechanisms, the arm is joined in an articulated manner on to the framework of the aircraft. The aircraft door is also joined in an articulated manner on to the free edge of the arm. This allows for the installing in position of the door in its frame.
In addition, the door is often movable in translational motion in relation to the arm in order to make possible the passage of the door behind the pressurising stoppers, in the case of fixed stoppers.
In one mechanism that is known, the arm is equipped at one end thereof with a deformable parallelogram providing for guidance in the phase of docking or retraction of the pressurising stoppers.
The requirement of precise guidance of the door, however, is contradictory with the need to decouple the door from/of the connecting mechanism once the door is closed.
In order to overcome this problem, the decoupling is brought about for example by means of deformable elastomer elements that are disposed either at the level of the pivot connections between the arm and the door, or interposed between the door and its guiding support members.